1. Field of the Invention
This invention relates to vapor compression refrigeration cycles, and more specifically to such cycles that use non-azeotropic working fluid mixtures with means to expand the temperature glide.
2. Description of the Related Art
A basis vapor compression refrigeration cycle is described in U.S. Pat. No. 2,492,725 issued Dec. 27, 1949 under the title "Mixed Refrigerant System". The subject system describes a refrigeration cycle that uses non-azeotropic working fluid mixtures. All of the following related art also use non-azeotropic working fluid mixtures.
A vapor compression heat pump system is described in U.S. Pat. No. 4,179,898 issued Dec. 25, 1979 under the title "Vapor Compression Cycle Device With Multi-Component Working Fluid Mixture and Method for Modulating Its Capacity." It describes a method to modulate the mass flow rate in a heat pump system to improve its efficiency that involves the use of high-pressure and low-pressure liquid accumulators and a high-pressure vapor separator.
Vapor compression heat pump systems are described in U.S. Pat. No. 4,217,760 issued Aug. 19, 1980 under the title "Vapor Compression Cycle Device With Multi-Component Working Fluid Mixture and Method for Modulating Its Capacity" and U.S. Pat. No. 4,218,890 issued Aug. 26, 1980 under the title "Vapor Compression Cycle Device With Multi-Component Working Fluid Mixture And Improved Condensing Heat Exchanger." They describe methods to modulate the mass flow rate in a heat pump system to improve its efficiency. Both describe the use of high-pressure and low-pressure liquid accumulators to achieve this modulation.
A vapor compression cycle is described in U.S. Pat. No. 4,218,919 issued Aug. 18, 1981 under the title "Vapor Compression Cycle Device With Multi-Component Working Fluid Mixture and Methods of Modulating the Thermal Transfer Capacity Thereof." It describes a system with two stages of evaporation and with separation at an intermediate pressure.
Still-like devices for separation of vapor and liquid in vapor compression refrigeration cycles are described in U.S. Pat. No. 4,769,999 issued Sept. 13, 1988 under the title "Liquid-Gas Contractor for Non-Azeotropic Mixture Refrigerant" and in "U.S. Pat. No. 4,781,738 issued Nov. 1, 1988 under the title "Liquid-Gas Contractor for Non-Azeotropic Mixture Refrigerant."